The Universal Serial Bus, conventionally referred to as USB, is a bus standard for inexpensively connecting external peripheral devices to a personal computer. USB provides an expandable, hot-pluggable serial interface that ensures a standard, low-cost connection for peripheral devices such as keyboards, mice, joysticks, printers, scanners, storage devices, modems, and the like. The popularity of the USB standard is evident as most computer manufacturers now include one or more USB interfaces for external USB peripherals as part of their systems. Commentators in the computer industry have noted that the USB standard is becoming the market's dominant I/O connectivity standard.
USB specification version 2.0 is the present generation of this peripheral connection for personal computers. It is intended as an upgrade for USB 1.1. The new standard provides additional bandwidth for multimedia and storage applications and also offers Plug-and-Play capability and full backward compatibility for legacy USB devices. USB 2.0 has a raw data rate at 480 Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12 Mbps. Originally, USB 2.0 was intended to go only as fast as 240 Mbps, but then, USB 2.0 Promoter Group increased the speed to 480 Mbps in October 1999.
Taking advantage of this quick connectivity standard are a variety of memory storage apparatus, one of which being a USB flash drive. In general, the USB flash drive is a small memory storage apparatus that interfaces with a host system through a USB connector. The apparatus uses low power non-volatile flash memory as its storage media instead of conventional rotating hard disk media. Examples of prior art USB flash drives include the M-Systems DiskOnKey™ 32 MB product and the Lexar JumpDrive™ 2.0 Pro.
In prior art USB flash drives, the systems typically use a USB connector (including an internal circuit board with contact terminals), an external circuit board for mounting the drive's other electrical components, and a protective exterior casing surrounding the external circuit board. Typically, the drive's other electrical components include a controller circuit, flash memory, a clock source, and various discrete components (such as de-coupling capacitors, surface mount resistors, and a light). The controller circuit may include interfacing circuitry for the flash memory and the USB host but sometimes such interfacing circuitry is implemented separately from the controller. In order to protect these components on the external circuit board, the protective exterior casing projects out from the USB connector to cover the external circuit board and the components mounted on it.
One problem in prior art USB flash drives is the large number of parts required to construct the drive. This typically results in undesirably high material and manufacturing costs for the drive. Additionally, the large number of parts cause the physical size of the drive to become undesirably large and cumbersome. The resulting size and configuration of such a prior art USB flash drive can often be inconvenient because the drive must extend out from the USB host system's mating USB connector interface. For example, many computers systems do not have much room for large, protruding peripheral devices attached to their external USB interface. If the USB host system is a desktop computer system situated against a wall, inserting such a prior art USB flash drive may require pulling the computer away from the wall into an undesirable new location that protrudes into the user's workspace. Likewise, if the USB host system is a laptop computer with a USB interface on the side of the laptop, inserting such a prior art drive on the side may protrude into the working area of the user's neighbor when on an airplane. As a result, laptop computers may be used in an environment where the ability to connect a protruding USB flash drive is limited to impossible.
Even when a prior art USB flash drive is connected to the back or side of a laptop computer, there is a real danger that the USB flash drive may snap off or break at the connector due to its unsupported protruding physical configuration. A user may accidentally bump the inserted USB flash drive and crack the connection between the USB connector and the external circuit board because the USB connector is the only part of the USB flash drive sufficiently supported relative to the laptop. Alternatively, a peripheral or power cord may get wrapped around the inserted USB flash drive on the back of the laptop and break the USB flash drive at the connector when the cord is accidentally pulled.
Accordingly, there is an urgent need for an improved USB flash drive that is reduced in size, is less expensive, and avoids possible damage to the drive from unsupported situations.